CVE-2026-111711

CRITICAL 9.8

Netcore NR256CN through 1.5.140116 Pre-Auth Stack Overflow via Boa user_ok()

CVSS Score

9.8

EPSS Score

0.0%

EPSS Percentile

0th

Netcore NR256CN through 1.5.140116 contains a pre-authentication stack overflow vulnerability in the Boa web server's user_ok() function, which copies Basic-auth usernames with unbounded strcpy() calls into 64-byte stack buffers. Unauthenticated attackers can send a username longer than 63 bytes to any protected /router/*.cgi route to crash the main Boa process or potentially execute code.

CWE	CWE-121
Vendor	netcore
Product	nr256cn
Published	Oct 16, 2026

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CVSS v3 Breakdown

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

Affected Versions

Netcore / NR256CN

0 ≤ 1.5.140116

References

NVD ↗ CVE.org ↗ EPSS Data ↗

github.com: https://github.com/lukadqq/netcore-router-public-refs/blob/a44d562736b41c944223297e9144d2ad7fa2aff1/2026.10.15-netcore-nr256cn-basic-auth-stack-overflow.md vulncheck.com: https://www.vulncheck.com/advisories/netcore-nr256cn-through-1.5.140116-pre-auth-stack-overflow-via-boa-user-ok

Credits

Zhou Ao Yin Luxing Lu Fangzhou Liu Xin